What’s New in Python 3.8

Post by codr7 » Tue, Oct 15, 2019, 2:15 AM UTC

jtdev wrote: post #111

Pxtl wrote: post #66

Ugh, I hate assignment expressions. I liked that they were missing from Python. I've been coding in algolesque languages for 20 years and hiding assignments inside of expressions instead of putting them on the left like a statement has always tripped me up.

But, but, but... now you don’t need to write that extra line of code! It’s going to make everything sooooo much better, code will practically write itself now. I’ll just leave this here: “There should be one—and preferably only one—obvious way to do it.”

Post by hermitdev » Tue, Oct 15, 2019, 2:16 AM UTC

svnpenn wrote: post #100

> In this example, the assignment expression helps avoid calling len() twice: if (n := len(a)) > 10: print(f"List is too long ({n} elements, expected Um, no it doesnt?: a1 = [10, 20, 30] n1 = len(a1) if n1 > 2: print(f'{n1} is greater than two')

Post by _v7gu » Tue, Oct 15, 2019, 2:20 AM UTC

jimktrains2 wrote: post #93

jorams wrote: post #74

Earlier quoted context omitted.

I may be missing something, but := is still only a 1 character difference, isn't it?

I should have said single-character additions or deletions . == And = have a levenstein distance of 1, == and := is 2. You can't simply make a typo and change an equality check to assignment. So, wiki defines levenstein distance as including substitution, but I was taught or at least remember it only being additions and deletions?

Post by ygrechuk » Tue, Oct 15, 2019, 2:22 AM UTC

3PS wrote: post #92

drdaeman wrote: post #86

Earlier quoted context omitted.

Coming from Perl, I used to want this badly, but then I thought that there's absolutely nothing wrong with m = re.match(...) if m is not None: pass Now, I wonder what you meant saying that single-line version is less error-prone, because I don't think so. I believe they're exactly the same in this regard, except for a bizarre case when someone would bastardize the code by putting some irrelevant lines between the ass…

The issue, in my opinion, is when you want something like this: while m := f(many, args): # do stuff with m Now, if you're writing this in Python 3.7, you often end up with some code duplication: m = f(many, args) while m: # do stuff with m m = f(many, args) # duplicate Or something like this: while True: m = f(many, args) if not m: break # do stuff with m Personally, I consider the last version to be the most elegan…

  def f_iter(many, args):
      while True:
          m = f(many, args)
          if m:
              yield m
          else:
              raise StopIteration
  ...
  for m in f_iter(many, args):
      # do stuff with m

Post by roywiggins » Tue, Oct 15, 2019, 2:29 AM UTC

Pxtl wrote: post #65

BurningFrog wrote: post #32

Earlier quoted context omitted.

> which itself is a result of limiting ourselves to the ASCII symbols that can be typed I think we're ready for programming languages using some visually good Unicode characters, instead of overloading `[]{}!@#$%^&*()-_/` for everything!

Oh god, this. I want a language that as I type, != Gets replaced with a proper ≠ not equals sign and proper symbols for AND, OR, and NOT.